Cementing or case-hardening material.



' tlNiTE-D STATES PATENT OFFICE.

ROBERT B. COREY, OF EDGEWOOD PARK, PENNSYLVANIA.

GLEMEN'I'ING on CASE-HARDENING MATERIAIL.

No Drawing. Application filed March 2 T; altwhom c t -may concern: in Be it known thatQ I, ROBERT Bl CounY, a citizen of the- United States, residing at lldgewood Park, in the county of Allegheny 5 and State of Pennsylvania, have invented certain new and useful Improvements in C(EmQ-Ilijlllg or Case-I-lardening Materials, of which the following is a specification.

My invention relates to the art otcemenl0 tation or case-hardcningof iron or steel and n1o1'e.partiei1la1-ly to materials used in'such cementing or case-hardening processes.

The objects of my invention are to increase the rapidity of the penetration of the carbon 16 into the iron or steel to be treated and to accomplish this result by the dry packing process Without the necessity of expensive or complicated apparatus.

My 'nvention consists of a mixture of vcan 20 bon or carbonaceous n'iaterial with a mate;

rial which acts to quickly transfer the bon to the surface of the iron or steel and to accomplish this transfer so quicklyfaaid eliectively that a further rapid transfer Yet, 5 ca "hon takes place between the molecules 0.; the heated iron or steel, resulting in a thick layer of highly carbonized.metal. upon the surface of the material so treated, the thickness of the layer dependingupon ,the dura- 0 tion of the treatment and the temperature to which the cementing materialand the iron or steel parts are subjected.

hlore particularly, my inventhm consists in the use of a. mixtureof carbon or carbona- 5 ceous material and oxid of n'iagnesiuni.

In carrying out my invention, the rarbon or carbonaceous material is preferably linrdy divided and the oxid of i'nagnesium is thow oughly mixed therewith. In practiced usually 40 add to the carbonaceous material about ten percent. by weight of oxid it magnesium but I have found that the percentage of mag nesium oxid present in the mixture is not essential to its action in the carboni'mition of the iron or steel and that, throughout the duration of the cementing encase-hardening p ncess,the said percentage is continually changing on. accountrof the absorption of carbon by the iron or steel, and other chemical changes that may take place in the heated Specification of Letters Patent.

Patented Jan. 2, 1917. 9,1916. Sria1No.87,515.

furnace. \Vhen the carbon becomes exhausted the remaining oxid of magnesium may be added to fresh carbon or carbonaceous material, thus reducing the cost of the cementing material to the minimum.

It is obvious that, instead of using oxid of magnesium for this process, the carbonate of magnesium may be used, as, upon the application of. heat, the carbonate of magnesium will be decomposed, gaseous oxid of carbon being liberated and the oxid of mag IlGSillll'] remaining, or both carbonate of magnesium and oxid of magnesium may be mixed with the carbon to form the cementing material.

l'haye found that the use of magnesiumi containing compounds as above mentioned, in the cementing or case-ha dening process, greatly reduces the length of time necessary to produce a carbonized layer of iron or steel of any desired depth.

lam aware that magnesium sulfate has been used in ccmentation processes. Upon heating the sulfate is dccon'iposed and suliurous gases are generated. Magnesium sulfate is very objectionable for this purpose, as it found that the suliurous gases lib "elated in contact with highly heated iron arepartially absorbed, producing a layer of sulfurous steel which is very weak and brit- SO tle, whereas, it there is no sulfur present the resulting steel will be both strong and tough, it being suitable for tools, automobile gears and steel structures that. are required to withstand severe shocks. l, therefore, confine myself to the use of magnesium compounds that have no sulfur in their composi tion.

I do not desire to limit myself to the exact materials and PIOPOl'tiUDS iflJUVO specified, but aimjin the appended claims to cover all mmlilications which are within the scope of myinvention.

' What I claim as new and desire to secitre by Letters Patent of the United States is- 1. cementing or case hardening material consisting essentially of carbonaceous material with not less than ten per cent. of oxid of magnesium.

2. Arementing or case-hardening ma-telmnalcof magncsimn, the total weight: 0L- the Saul mugnesunn cumpmmds bemg not less than ten per cent. of the weight of the 10 j said cementing material.

In witneas whereof I have set my hand this Jth day of March, 1916.

. ROBERT B. COREY.

Fmcn B. Conny,

M. ME'NfmL. 

